Periadventitial dissection of the superior mesenteric artery for locally advanced pancreatic cancer: Surgical planning with the “halo sign” and “string sign”

Most patients diagnosed with pancreatic cancer are classified as nonoperative candidates based on the contemporary guidelines of resectability. The advent of more potent control of systemic disease using neoadjuvant chemotherapy has enabled more aggressive operative interventions. In our multidisciplinary practice, patients with Stage III, locally advanced pancreatic cancer and superior mesenteric artery (SMA) encasement are now carefully triaged with high quality, preoperative imaging to determine if they can be considered candidates for operative resection with periadventitial dissection of the SMA. Patients displaying a “halo sign,” where the encased SMA remains fully patent and free from arterial invasion, are now candidates for SMA periadventitial dissection. This procedure involves the surgical stripping of the infiltrated neurolymphatic tissue off the SMA leaving behind a bare “skeletonized artery.” Alternatively, the “string sign” involving the SMA confers a more likely case of arterial invasion, where a complete oncologic resection cannot be achieved successfully. This method of patient selection in case of SMA involvement abandons the traditional metrics of circumferential degrees of the arterial encasement to guide surgical decisions. Our institutional approach has allowed us to meaningfully expand our operative methods of resection with the potential for improved longitudinal outcomes to pancreatic cancer patients who were deprived historically from the more effective and possibly curative treatment.     

Towards a Neurotransmitter-Based Retinal Prosthesis Using an Inkjet Print-head

Electronic chips that provide a patterned stimulus to cells in the retina may provide a viable treatment for age-related macular degeneration. A surrogate MEMS device, in the form of a print-head from a desktop printer, has been used to eject a pattern of neurotransmitters (bradykinin) onto living rat pheochromocytoma (PC12) cells. Fluorescent calcium imaging was used to measure the patterned stimulation of individual cells. The chemical stimulation of cells by directed microfluidic delivery may have applications in retinal prosthetic devices, and in other prosthetic implants in the nervous system.     

Nuclear medicine Competitors or collaborators?

Here in the USA

Nuclear medicine Competitors or collaborators?     

Activation of chick tendon lysyl oxidase in response to dietary copper

Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10-30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the functional activity of lysyl oxidase and the copper content of chick tendon are both related to dietary copper intake. Chicks (1-d old) were fed diets (basal copper concentration, 0.4 microg/g diet) to which copper was added from 0 to 16 microg/g diet. Liver and plasma copper levels tended to normalize in chickens that consumed from 1 to 4 microg copper/g of diet, whereas tendon copper concentrations suggested an unusual accumulation of copper in chickens that consumed 16 microg copper/g diet. The molecular weight of lysyl oxidase was also estimated using matrix-assisted laser desorption ionization/time-of-flight/mass spectrometry (MALDI/TOF/MS). A novel aspect of these measurements was estimation of protein mass directly from the surface of chick tendons and aortae. Whether copper deficiency (0 added copper) or copper supplementation (16 microg copper/g of diet) caused changes in the molecular weight of protein(s) in tendon corresponding to lysyl oxidase was addressed. The average molecular weight of the peak corresponding to lysyl oxidase in tendon and aorta from copper-deficient birds was 28,386 Da +/- 86, whereas the average molecular weight of corresponding protein in tendon from copper-supplemented birds was 28,639 Da +/- 122. We propose that the shift in molecular weight is due in part to copper binding and the formation of lysyl tyrosyl quinone, the cofactor at the active site of lysyl oxidase.     

Helical CT amniography of congenital diaphragmatic hernia

OBJECTIVE: Accurate prenatal diagnosis of congenital diaphragmatic hernia is important for perinatal planning and potential fetal surgery. We describe the application and usefulness of helical CT amniography in the evaluation of suspected congenital diaphragmatic hernia in three fetuses. CONCLUSION: Helical CT amniography is an efficient means for evaluation of congenital diaphragmatic hernia. Accurate diagnosis was made in all three patients.     

Pseudomembranous colitis: spectrum of imaging findings with clinical and pathologic correlation.

Pseudomembranous colitis (PMC) is a potentially life-threatening acute infectious colitis caused by one or more toxins produced by an unopposed proliferation of Clostridium difficile bacteria. PMC is characterized by the presence of elevated, yellow-white plaques forming pseudomembranes on the colonic mucosa. These plaques can be visualized at both pathologic analysis and endoscopy. Plain radiography, contrast enema studies, and computed tomography (CT) are useful in the evaluation of PMC. Plain radiography of the abdomen can demonstrate polypoid mucosal thickening, "thumbprinting" (wide transverse bands associated with haustral fold thickening), or gaseous distention of the colon. A toxic megacolon with distention and occasionally pneumoperitoneum may be seen in the most severe cases of PMC involving perforation. At contrast enema studies, the primary finding in mild cases of PMC is small nodular filling defects representing the mucosal plaques. With more extensive colonic involvement, the plaques are larger and coalesce to form an irregular bowel wall margin. Mural thickening and wide haustral folds caused by intramural edema may also be seen. A contrast enema study is contraindicated in patients with severe PMC due to the danger of perforation. Common CT findings include wall thickening, low-attenuation mural thickening corresponding to mucosal and submucosal edema, the "accordion sign," the "target sign" ("double halo sign"), pericolonic stranding, and ascites. Familiarity with these imaging characteristics may allow early diagnosis and treatment and prevent progression to more serious pathologic conditions.     

Fetal response to neutral gas and liquid media for intraamniotic distension

PURPOSE: This study was aimed at comparing the effects of a neutral liquid and a neutral gas used as intraamniotic media on umbilical blood flow, O2 delivery, blood pressure, acid-base status, and electrolytes in the fetus at escalating intraamniotic pressures. METHODS: Eight fetal lambs underwent invasive monitoring of common umbilical blood flow, blood pressure, blood gases, sodium, and hematocrit, as intraamniotic pressure was raised from 0 to 30 mm Hg. The animals were divided equally in two groups depending on the intraamniotic medium used (group I, warmed saline and group II, air). Maternal systemic blood pressure, O2 saturation, and temperature were kept constant. RESULTS: In each group, a threshold level of intraamniotic pressure was evident, above which there was a significant decrease in the common umbilical artery blood flow, with concomitant fetal hypoxemia and hypercarbia. This intraamniotic pressure threshold was 20 mm Hg in group I (saline), but only 15 mm Hg in group II (air). CONCLUSIONS: Although both a neutral liquid and a neutral gas can safely be used as intraamniotic media, a neutral liquid medium allows for a wider range of safe intrauterine working pressure (0 to 20 mm Hg), as compared with a neutral gas (0-15 mm Hg).